Nutritional assessment of Australian canola meals. I. Evaluation of canola oil extraction method and meal processing conditions on the digestible value of canola meals fed to the red seabream (Pagrus auratus, Paulin)

Abstract

This study assessed the nutrient and energy digestibility of a variety of canola protein products that were produced by processing canola meal under different conditions, using the red seabream, Pagrus auratus. The test canola protein products included solvent‐extracted canola meal, expeller‐extracted canola meal alone or subjected to one of two different heat treatments (120 or 150°C for 30 min), and expeller meal further processed to produce a canola protein concentrate (CPC). Solvent‐extracted soybean meal was also included in the study as a reference ingredient. Daily feed intake and blood thyroid hormone levels over the experimental period were also examined. The total digestible protein content of the expeller‐ and solvent‐extracted canola meals was 356 and 358 g per kg dry matter (g kg DM−1) respectively. The total digestible energy content of the expeller‐ and solvent‐extracted canola meals was 14.23 and 8.60 MJ kg−1 respectively. The organic matter digestibilities of the solvent‐extracted canola meal were poorer than noted for the expeller‐ and solvent‐extracted soybean meal. Notably, the two sources of canola meals used in this study (solvent and expeller meals) did not cause problems with declining feed intakes or changes to blood levels of thyroid hormones when included in the diets of the fish at a 30% level, and the diets were fed over a 3‐week period. The preparation of a CPC resulted in gains in total digestible energy, but a reduction in the amount of total digestible protein, relative to the expeller canola meal from which it was produced. However, the protein concentrating process marginally reduced the relative digestible value of the protein content. Heating expeller meal at 120 or 150°C for 30 min resulted in progressive reductions of all nutrient and energy digestibilities.

Effects of canola meal on physiological and biochemical parameters in rainbow trout (Oncorhynchus mykiss)

“…the diet with the highest overall inclusion of canola meal. However, Glencross et al (2003b) suggested that canola meals (Solvent & Expeller -extracted canola) could be included in proteinlimiting diets of red sea bream at up to 600 g kg )1 of the digestible protein content, without affecting the growth rate Table 7 Fatty acid compositions of liver in rainbow trout fed different levels of canola meal. Others have reported that rapeseed meal and canola protein concentrates could not totally replace fish meal in diets for rainbow trout unless a feed attractant was added .…”

Nutritional assessment of Australian canola meals. II. Evaluation of the influence of the canola oil extraction method on the protein value of canola meals fed to the red seabream (Pagrus auratus, Paulin)

“…The findings of this study also support that, when either solvent‐or expeller‐extracted canola meals are included in protein‐limiting diets for red seabream, on an equivalent digestible protein basis and the diets are subsequently fed on a restrictive basis, then they are equally useful as feed ingredients to the fish. However, it should be noted that there were subtle differences in the digestibility values of these two canola sources (Glencross et al 2003b). This difference in its own right has important implications for the respective value of each of the meals when used in diets for fish.…”

Investigation of the nutritional requirements of Australian snapper Pagrus auratus (Bloch & Schneider, 1801): apparent digestibility of protein and energy sources

“…Despite the promise of the Australian snapper industry, little has been done with regard to diet development (Quartararo, Allan & Bell 1998b) and farmers still rely on feeds formulated specifically for Atlantic salmon Salmo salar or barramundi Lates calcarifer . More recently, specific digestibility coefficients for snapper fed Australian lupin and canola meals have been published (Glencross, Curnow, Hawkins, Kissil & Peterson 2003; Glencross, Hawkins & Curnow 2004). In contrast, digestibility coefficients for a diverse range of ingredients have been published for the red sea bream (Yamamoto, Akimoto, Kishi, Unuma & Akiyama 1998) and the gilthead sea bream (Nengas, Alexis, Davies & Petichakis 1995; Lupatsch, Kissil, Sklan & Pfeffer 1997).…”